Exchange reactions, of hydrogen

Isotopic Exchange Reactions. Exchange reactions between the isotopes of hydrogen are well known and well substantiated. The equihbrium constants for exchange between the various hydrogen molecular species have been documented (18). Kinetics of the radiation-induced exchange reactions of hydrogen, deuterium, and tritium have been critically and authoritatively reviewed (31). The reaction T2 + H2 — 2HT equiUbrates at room temperature even without a catalyst (30). 

J. W. Pyper and C. K. Briggs, Kinetics of the Radiation-induced Exchange Reactions of Hydrogen, Deuterium, and Tritium, Eawrence Eipermore Eaboratory Report... 

Horiuti, I., Polanyi, M. Exchange Reactions of Hydrogen on Metallic Catalysts. Transactions of the Faraday Society. 1934, 30, 1164 - 1172. 

Ichikawa, M., Soma, M., Onishi, T., Tamaru, K. Reactivity of Electron Donor-Acceptor Complexes. Part. 8. Exchange Reaction of Hydrogen between Various Phthalocy-anine EDA Complexes and Acetylene or Molecular Hydrogen. Trans. Faraday Soc. 63, 1215(1967). 

Hoiiuti J, Polanyi M (1930) Exchange reactions of hydrogen on metallic catalysts. Trans Faraday Soc 30 1164... 

A longstanding controversy existed on the detailed reaction mechanism of the elementary exchange reaction of hydrogen... 

The stereochemistry observed in hydrogen-exchange reactions of carbanions is very dependent on the conditions under which the anion is formed and trapped by proton... 

The earliest attempts to prepare deuterated steroids were carried out by exchange reactions of aliphatic hydrogens with deuterium in the presence of a surface catalyst. Cholesterol, for example, has been treated with platinum in a mixture of deuterium oxide and acetic acid-OD, and was found to yield... 

The catalytic activity in relation to a given reaction occurring on the surface is characterized by the rate g of this reaction, i.e., by the amount of reaction products formed under the given external conditions per unit time on unit surface area. An expression for g has different forms for different reactions. For the reactions of hydrogen-deuterium exchange, oxidation of CO, and synthesis of H2O2, this expression will be derived in Sections III, IV, and V, respectively. 

Thus, Kohn and Taylor (40) point out that the y irradiation of zinc oxide which speeds up the reaction of hydrogen-deuterium exchange lowers the magnitude of the effect when a donor impurity is introduced into the specimen. 

Lunsford and Leland (42) studied the reaction of hydrogen-deuterium exchange on crystals of MgO containing V-centers. As known, a Y-center in an ionic crystal, being a cationic vacancy with a hole localized near it, plays the role of an acceptor. These authors have found that the photocatalytic effect is intensified as the concentration of V-centers in a crystal increases, which is in accord with the experiments carried out by Kohn and Taylor. 

Freund (44) studied the influence of ultraviolet light on the catalytic activity of zinc oxide in relation to the reaction of hydrogen-deuterium exchange. The author noted that the photocatalytic effect was positive and that it decreased with rising temperature. 

Hydrogen isotope exchange reactions of organic compounds in liquid ammonia, 1, 156... 

The rate of the observed exchange reaction of the phosphine ligands in the dihydrides increases in the above-listed series of phosphines from PMe3 to P(n-butyl)3 (Table 12.1), which in turn correlates with the activity of the corresponding complexes as hydrogenation catalysts. 

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